Performance and Quality
When it comes to portability, ASUS is hard to top. ASUS's Eee PC netbooks are generally superior to any MSI Wind netbook. That isn't to say that MSI's Wind line is terrible, but the ASUS Eee PC is essentially the cream of the crop, offering the best battery life, good keyboards, and great aesthetic design. The Wind netbooks are a decent jack-of-all-trades but simply can't compare to the Eee PC.
This trend repeats itself in the ultraportable market. MSI offers both the X340 and X600 series thin-and-light laptops, but neither of them hold a candle to ASUS's UL series. Unlike with the netbooks, however, ASUS's victory in this category isn't just due to its own excellence. MSI's X series laptops simply are not very good. Although they do offer striking design, they have poor performance, relatively poor battery life and simply feel cheap when handled.
The verdict is still out on the battle between MSI and ASUS in the mainstream and gaming laptop markets. ASUS has never been that strong in the mainstream market, but ASUS gaming laptops have always been excellent. MSI has a lot to live up to if they hope to match ASUS. Early reviews indicate that MSI has a fighting chance, but ASUS is still the safer bet for those who want a high-performance gaming laptop.
MSI's long term reliability is unknown. The company's laptops are fairly new, and MSI's sales are still small compared to a company like ASUS, so there isn't enough date to accurately judge the long term reliability of MSI's laptops. The reliability of ASUS, however, is very well known. ASUS has the highest laptop reliability ratings in the industry.